In a case-control study the effects of smoking and the use of oral contraceptives were examined in 83 patients with Crohn's disease and 37 patients with ulcerative colitis in comparison with members of the general population who served as controls. After controlling for oral contraceptives, smokers were found to have a significantly elevated relative risk of contracting Crohn's disease of 3.0 (1.3 to 6.8). Patients on oral contraceptives for more than three years had an elevated risk for Crohn's disease of 4.3 (1.3 to 14.4); this elevated risk was, however, found only in the non-smoking group. In the case of ulcerative colitis, the relative risk in smokers was significantly lower (0.21 [0.04 to 0.91]) than in non-smokers. The use of oral contraceptives does not represent a risk factor for ulcerative colitis. While smoking has been established as a risk factor in the development of inflammatory bowel disease, the role of oral contraceptives in the aetiology of this condition remains unclear.
The role of environmental factors in the risk for Crohn's disease (CD), an inflammatory bowel disease (IBD), was investigated in a North Island-based New Zealand case-control cohort. A total of 315 CD patients and 536 controls were recruited through various sources to the Auckland CD Risk Factor Study. As well as demographic characteristics, the self-reported questionnaire included (1) smoking and drinking alcohol, (2) breastfeeding in infancy, (3) early life exposures to allergens and microbes, (4) health conditions lasting 6 months or longer and (5) taking antibiotics and any medications. There was strong evidence for familial associations of the disease, and minor effects of birth order and number of siblings. Being a smoker, especially over a long time period, and exposure to smoking during childhood and adolescence periods increased risk, whereas drinking alcohol at least once per week showed a slight protective effect. Long term use of the oral contraceptive pill increased the risk of developing CD, but breastfeeding and immunisation during infancy showed no significant association. Long term and debilitating illness (lasting 6 months or more), taking antibiotics prior to developing CD, or taking four or more antibiotics or any regular medication in a year during adolescence substantially increased the CD risk. Having a pet during childhood was a protective factor, but regularly feeding an animal was not sufficient to protect. Many of these significant factors are likely to impact on the colonic microflora and/or immune system. We conclude that, in addition to strong evidence for genetic associations, factors likely to impact on immune response or reduce early exposure to microbes provide a main risk factor for CD in this New Zealand population.
General OB/GYNSystemic Lupus ErythematosusAutoimmune Disease RiskRisk Factor Analysis
Open Access
To assess risk factors associated with systemic lupus erythematosus (SLE) in the Mexican population. A case-control study was conducted on June 1996, at the Reumathology Clinic of Hospital de Especialidades del Centro Médico Nacional Siglo XXI (HE CMN), Instituto Mexicano del Seguro Social, in Mexico City. Cases were one hundred thirty subjects with four or more SLE criteria and disease evolution of +/- 5 years. Controls were hospitalized patients with acute diseases but without autoimmune diseases. Cases and controls were matched 1:1 by age and gender; both groups were evaluated by direct interview through a structured questionnaire. The following genetic family history of SLE and connective tissue disease; socioedemographic (ethnicity, geographic distribution, education, monthly income); hormonal (use of oral contraceptives, replacement therapy and gynecoobstetric background); environmental (use of hair products, living with dogs, bacterial/viral infections, and allergies). Statistical analysis consisted of odd ratios (OR) with 95% confidence intervals (CI) and multivariate analysis using logistic regression. The multivariate model showed association with family history of SLE (OR 4.2, CI 95% 1.17-15.2), family history of connective tissue disorder (OR 2.6, CI 95% 1.15-4.5), use of oral contraceptives for more than one year (OR 2.1, CI 95% 1.13-4.3), repetitive pharyngitis (OR 2.1, CI 95% 1.18-3.6), and use of medications (OR 5.0 IC 95% 1.62-21.6). No association was found with socieconomic status, hair dye products, asthma, or allergies. Genetic factors, such as family history of SLE and connective tissue disease in first-degree relatives, persist as important factors in the development of SLE. Other factors, such as use of some drugs, oral contraceptives, and repetitive pharyngitis, may also favor the onset of disease in genetically susceptible hosts. //www.insp.mx/salud/index.html.
Contraception/ComparisonAutoimmune Disease RiskSystemic Lupus ErythematosusNurses Health Study
To examine the relationship between past use of oral contraceptives (OCs) and development of systemic lupus erythematosus (SLE). Prospective cohort study of 121,645 women who were followed up every 2 years between 1976 and 1990 as part of the Nurses' Health Study. Women were classified as never users or past users of OCs based on self-report. Incidence of SLE was defined by 1) strict American College of Rheumatology (ACR) classification criteria (> or = 4 ACR criteria), 2) > or = 4 ACR criteria and any physician's diagnosis, 3) > or = 4 ACR criteria and diagnosis by an ACR-certified rheumatologist, 4) > or = 3 ACR criteria, or 5) diagnosis by a physician even if the patient did not meet the ACR criteria. Compared with never users of OCs, and after adjusting for age and ever use of postmenopausal hormones, the relative risk (95% confidence interval [95% CI]) for the incidence of SLE in the women who had definite cases of SLE (> or = 4 ACR criteria) (n = 99) was 1.4 (0.9-2.1) for past users of OCs. Using the most stringent case definition (ACR criteria plus a diagnosis of SLE by an ACR member) (n = 58), the relative risk for past users compared with never users was 1.9 (95% CI 1.1-3.3). No relationship was observed between duration of OC use or time since first use and the risk of developing SLE. Past use of OCs was associated with a slightly increased risk of developing SLE. The decision to use hormonal contraception must be individualized, but the small absolute risk observed for the development of SLE in white women should not be a dominant factor in the decision.
The authors undertook a case-control study to explore the many factors that have been postulated to be related to the etiology of systemic lupus erythematosus. A total of 195 cases of systemic lupus diagnosed in the Philadelphia, Pennsylvania, metropolitan area between 1985 and 1987 were compared with 143 controls, friends of the cases matched to them according to age (+/- 5 years) and sex. Through personal interviews and chart reviews, data were collected on demographic factors, personal and familial medical history, reproductive history, medication history, and environmental exposures. Associations were found between systemic lupus erythematosus and having a family history of autoimmune disease (age-, sex-, and race-adjusted odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.2-4.6), a history of shingles (adjusted OR = 6.4, 95% CI 1.4-28.0), a history of hives (adjusted OR = 1.8, 95% CI 1.1-3.0), and a history of medication allergies (adjusted OR = 2.6, 95% CI 1.5-4.5). No association was present between systemic lupus erythematosus and either any use or recent use of oral contraceptives (e.g., OR = 0.6 (95% CI 0.2-1.4) for use in the 3 years prior to diagnosis), family history of multiple other diseases, or a history of numerous other infections or various other types of allergies. Thus, these data indicate that systemic lupus erythematosus is associated with a family history of autoimmune diseases, a history of shingles, and a history of allergies. In contrast, if the development of systemic lupus is affected by use of oral contraceptives, this effect must be extremely modest. These findings may help clarify the possible pathogenesis of systemic lupus erythematosus, and they provide clues as to when the presence of systemic lupus should be suspected.